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A VARIABLE ILLUMINATION OPTICAL SYSTEM

IP.com Disclosure Number: IPCOM000023355D
Original Publication Date: 1977-Jun-30
Included in the Prior Art Database: 2004-Mar-30
Document File: 2 page(s) / 447K

Publishing Venue

Xerox Disclosure Journal

Abstract

An electrophotographic printing machine optical system em-ploying a screen to modulate the light produced thereby. The intensity of the light image is varied as a function of screen position. Screen 28 is disposed closely adjacent to photo-conductive surface 12 of drum 10. Drum 10 rotates in the direction of arrow 14. Screen 28 is mounted slideably in rail 74. Rack 76 is secured integral to screen 28. Worm gear 28 meshes with rack 76. Rotation of worm gear 78 translates rack 76. Translation of rack 76 moves screen 28 relative to photo-conductive surface 12 to adjust the spacing therebetween. As screen member 28 moves, the intensity of the light image transmitted therethrough is suitably adjusted. This is achieved by regulating the intensity of the light rays gen-erated by lamps 26, Thus, for any position of screen 28, there is an optimum light ray intensity.

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Page 1 of 2

XEROX DISCLOSURE JOURNAL

A VARIABLE ILLUMINATION OPTICAL
SYSTEM
Wayne L. Kidd

Proposed Classification
U.S. Cl. 355/3
Int, Cl. G03g 15/00

An electrophotographic printing machine optical system em~
ploying a screen to modulate the light produced thereby. The
intensity of the light image is varied as a function of screen
position. Screen 28 is disposed closely adjacent to photo-~
conductive surface 12 of drum 10. Drum 10 rotates in the
direction of arrow 14. Screen 28 is mounted slideably in rail
74. Rack 76 is secured integral to screen 28. Worm gear 28
meshes with rack 76. Rotation of worm gear 78 translates rack
76. Translation of rack 76 moves screen 28 relative to photo-
conductive surface 12 to adjust the spacing therebetween. As
screen member 28 moves, the intensity of the light image
transmitted therethrough is suitably adjusted. This is
achieved by regulating the intensity of the light rays gen-~
erated by lamps 26, Thus, for any position of screen 28, there
is an optimum light ray intensity.

PIG. /

PIG. 2

Volume 2 Number 3 May/June 1977 71

[This page contains 1 picture or other non-text object]

Page 2 of 2

A VARIABLE ILLUMINATION OPTICAL SYSTEM (Cont~d)

The control system regulates the intensity of the light rays
generated by light source 26 as a function of the spacing
between screen 28 and photoconductive surface 12, Motor 80 is
controlled by an error signal developed by comparator 82.
Comparator 82 compares the reference signal with a signal
indicating the position of screen 28. Motor 80 moves screen
28 until the error signal from comparator 82 is nulled.
Screen 28 is connected to the wiper arm of potentiometer 84.
Movement of the wiper arm of potentiometer 84 adjusts the
voltage output therefrom, Potentiometer 84 provides an indi-
cation of the position of s...